O Donnell, Gerard J. An investigation into the deck officers' appreciation of the practice of using the sextant for navigation in 2016 / Gerard J. O Donnell. - 35 pages : color illustrations ; 30 cm - B.Sc. (Hons) Nautical Science . Includes bibliographical references. Subjects--Topical Terms: Aids to navigationSextant Dewey Class. No.: B.Sc. Nautical Science